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higher orbit. Therefore the upper stage doesn’t have to provide as much energy to the
system and can therefore be smaller.
Gross Weight Weight
Dry Dry Weight
Structure
Propulsion Propulsion
Power
Dry Weight Margin
14,270 lb
2,180 lb
1,160 lb
370 lb
130 lb
280 lb
Dry Weight Margin
15%
Power
7%
Propulsion
19%
Figure 35: Weight Breakdown of GT RASCAL 2nd Stage.
Structure
59%
The third stage of the GT RASCAL also benefits from the weight savings in the
first stage. The third stage is 500 lbs lighter than the baseline. This can be attributed to
the same energy savings as the second stage as well as the fact that a fourth stage has
been added.
Gross Weight
Dry Weight
Structure
Propulsion
Power
Avionics
Dry Weight Margin
2,750 2,750 lb
370 370 lb
110 110 lb
100 100 lb
30 lb
180 180 lb
50 lb
Dry Weight Margin
10%
Avionics
40%
Figure 36: Weight Breakdown of GT RASCAL 3rd Stage.
Power
5%
Structure
23%
Propulsion
22%
The Fourth and final stage of the GT RASCAL design utilizes a very small
apogee kick motor. This motor is just over 32 lbs with a dry weight of 9lbs. This engine
was sized using a simple two body orbital mechanics as well as the rocket equation
∆ (6)
V = g 0I
sp
ln( MR)
This finite burn is relatively accurate since the circularization burn is very short.
It is also informative to look at the percentage of fuel used in each phase of the
first stages flight (Figure 37). From this figure it can be seen that the majority of the fuel
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